Conformal Li2O2 Growth and Decomposition Within 3D Lithiophilic Nanocages of Metal–Organic Frameworks for High‐Performance Li─O2 Batteries

Abstract Li─O 2 batteries (LOBs) have the largest theoretical capacity among current batteries, but the irreversible growth and decomposition of Li 2 O 2 products in positive electrodes cause dramatic degradation of their capacities over charging–discharging cycles. Herein, a metal–organic framework is reported with bipyridinic N linkers attached to graphene (bpyN‐MOF/g) as a positive electrode material to overcome the challenge. The bpyN‐MOF/g promotes conformal Li 2 O 2 growth during discharging, while allowing Li 2 O 2 decomposition at a low overpotential (0.487 V vs Li + /Li at 200 mA g c −1 ) during charging process, outperforming the Pt/C‐based electrode (0.857 V). Moreover, 3D‐tomography and density functional theory calculations consistently support the Li 2 O 2 growth and decomposition mechanism inside bpyN‐MOF/g. Furthermore, bpyN‐MOF/g//Li LOBs achieve an exceptional discharge capacity (17 275 mAh g c −1 at 100 mA g c −1 ) and steady cycling for 270 cycles at 1000 mAh g c −1 under 2000 mA g c −1 . Additionally, high gravimetric capacity at low mass loadings (0.27–0.44 mg cm −2 ) and stable cycle operation at a high areal current density (0.5 mA cm −2 ) open new opportunities for various practical applications.